The Florida Department of Health has issued a warning against a deadly brain-eating amoeba after 12-year-old Zachary from Florida got infected by the parasite while knee boarding at a water-filled ditch close to his house on 3 August.

The most favourable condition for the deadly parasite Naegleria fowleri to breed is stagnant, high water temperatures with low levels, officials said according to a report in Fox2Now. The officials have warned public to stay away from fresh water with these conditions.

Zachary's condition was detected after the otherwise active seventh-grader started sleeping too much. His family members took him to hospital, where doctors diagnosed him with primary amoebic meningoencephalitis and later performed a brain surgery on him.

Zachary is now battling the disease at the Miami Children's Hospital.

Last month, another 12-year-old from Arkansas, Kali Hardig fell victim to the deadly parasite but miraculously became the third survivor in the last 50 years to the rare condition.

She was treated at Arkansas Children's Hospital in Little Rock.

"We continue to be amazed by Kali's progress," Kali's family said in a statement Thursday.

"Today she's able to sit up on her own, write some words on a white board and stand with assistance for very brief stretches. She's even able to throw and catch a ball with her therapists. We are grateful for the continued prayers from Kali's supporters, which no doubt drive her recovery", the statement further said.

Kali's pysician, Dr. Vikki Stefans at Arkansas Children's Hospital's Progressive Rehab Unit, said there is no doubt she will survive, but the only question is how well.

Although there are very few people to have ever got the parasite, 99% of those who get it, do not survive.

"This infection is one of the most severe infections that we know of," Dr. Dirk Haselow of the Arkansas Department of Health told CNN affiliate WMC-TV.

Kali was treated with experimental anti-amoeba drug they received directly from the CDC and the same drugs are being given to Zachari as well.

According to the Centers for Disease Control and Prevention, the disease is not communicable and spreads rapidly, resulting in death within days.

The symptoms of the infection could be a change in the sense of smell or taste, fever, sudden headache, nausea, vomiting, confusion and loss of balance.